ANTIVIRAL Flashcards
Acyclovir MOA
guanosine analog, is preferentially phosphorylated by viral thymidine kinase and inhibits
viral DNA polymerase, halting viral DNA synthesis by chain termination
TK is produced at a ? rate in herpes
infected cells than in noninfected cells
higher
Rapid intravenous infusion of acyclovir
reversible
obstructive nephropathy16
prodrug of its active metabolite, acyclovir
Valacyclovir
Valacyclovir vs Acyclovir
enhanced bioavailability
converts rapidly completely into acyclovir
Valacyclovir has been shown to be superior to acyclovir
shortening the duration of pain from post-herpetic
neuralgia associated with zoster patients
Longer intracellular half-life than acyclovir
Famciclovir
prodrug of penciclovir
Famciclovir
CMV retinitis in immunocompromised patients and for CMV prophylaxis in
transplant patients
Gancyclovir
PO Gancyclovir
has very poor bioavailability
Adverse effects Gancyclovir:
Bone marrow suppression, neutropenia, and thrombocytopenia; worsened
by concomitant administration of AZT
Foscarnet MOA
Noncompetitive inhibition of viral DNA polymerases at the pyrophosphate-binding site
Foscarnet active against viruses
resistant to acyclovir, famciclovir, or ganciclovir on basis of altered kinase activities
Does not require phosphorylation for antiviral activity
Penile erosions
Foscarnet
HSV or VZV infection resistant to acyclovir ganciclovir-resistant CMV
Foscarnet